Log: https://pastebin.com/z3Nx7wyA
Using official GIMX adapter:
the gaming target: PS4
the game: GT Sport
the controller: OSW Wheel, HE Pedals
EMU: G29Ps4
Behavior: GIMX starts, In PS4 only the PS button mapping is working no other buttons, no pedals or wheel input working.

Solution & Tips:
The solution was to install the latest Logitech gaming software.
This should be on the included instructions if one is trying to emulate a Logitech device. I could not find it clearly stated on the wiki.

If you are using a 20nm MIGE direct drive I recommend putting all the wheel settings in game to lowest value and in the gimx ffb config put your FFB values between 60-70.

Log: https://pastebin.com/z3Nx7wyA
Using official GIMX adapter:
the gaming target: PS4
the game: GT Sport
the controller: OSW Wheel, HE Pedals
EMU: G29Ps4
Behavior: GIMX starts, In PS4 only the PS button mapping is working no other buttons, no pedals or wheel input working.